build-args are not propagated as env vars for RUN statements for buildah bud

[Conan-Kudo]

Description

When building a container with buildah bud with --build-arg passed in, the args are not available as env vars for use inside of the container build.

This did last work in buildah in either 1.11.x or 1.14.x, and seems to be broken as of buildah 1.15.

Steps to reproduce the issue:

1. buildah bud --build-arg PHP_VERSION=7.0 --build-arg OS_VERSION=16.04 -f Containerfile-sample

Containerfile-sample has the following contents:

FROM ubuntu:16.04

# Base Requirements
RUN apt-get update -y && \
  DEBIAN_FRONTEND=noninteractive apt-get install -y \
  sudo \
  apt-transport-https \
  curl \
  rsync \
  unzip \
  locales \
  jq \
  bindfs \
  software-properties-common \
  iputils-ping

# Add 3rd party repos for non-standard Sources
RUN if [ "$OS_VERSION" = "16.04" ]; \
  then export LANG=en_US.UTF-8; \
  locale-gen en_US.UTF-8; \
  add-apt-repository ppa:deadsnakes/ppa -y; \
  add-apt-repository ppa:ondrej/php -y; \
  #elif [ $OS_VERSION = "18.04" ]; \
  fi

# Install the specified PHP version
RUN rm -rf /var/lib/apt/lists/* && \
  apt-get update -y && \
  DEBIAN_FRONTEND=noninteractive apt-get install -y \
  php${PHP_VERSION} \
  php${PHP_VERSION}-cli \
  php${PHP_VERSION}-curl \
  php${PHP_VERSION}-json \
  php${PHP_VERSION}-xml \
  php${PHP_VERSION}-mbstring \
  php${PHP_VERSION}-zip \
  php${PHP_VERSION}-mysql

Describe the results you received:
The container builds with the second RUN statement completely skipped.

Describe the results you expected:
The container builds with the second RUN statement executed.

Output of rpm -q buildah:

buildah-1.15.1-2.module_el8.3.0+475+c50ce30b.x86_64

Output of buildah version:

Version:         1.15.1
Go Version:      go1.14.7
Image Spec:      1.0.1-dev
Runtime Spec:    1.0.2-dev
CNI Spec:        0.4.0
libcni Version:
image Version:   5.5.1
Git Commit:
Built:           Thu Jan  1 00:00:00 1970
OS/Arch:         linux/amd64

Output of cat /etc/*release:

CentOS Linux release 8.3.2011
NAME="CentOS Linux"
VERSION="8"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"
CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"
CentOS Linux release 8.3.2011
CentOS Linux release 8.3.2011

Output of uname -a:

Linux c63a76fde430 5.9.16-200.fc33.x86_64 #1 SMP Mon Dec 21 14:08:22 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf:

# This file is is the configuration file for all tools
# that use the containers/storage library.
# See man 5 containers-storage.conf for more information
# The "container storage" table contains all of the server options.
[storage]

# Default Storage Driver
driver = "overlay"

# Temporary storage location
runroot = "/var/run/containers/storage"

# Primary Read/Write location of container storage
graphroot = "/var/lib/containers/storage"

# Storage path for rootless users
#
# rootless_storage_path = "$HOME/.local/share/containers/storage"

[storage.options]
# Storage options to be passed to underlying storage drivers

# AdditionalImageStores is used to pass paths to additional Read/Only image stores
# Must be comma separated list.
additionalimagestores = [
]

# Remap-UIDs/GIDs is the mapping from UIDs/GIDs as they should appear inside of
# a container, to the UIDs/GIDs as they should appear outside of the container,
# and the length of the range of UIDs/GIDs.  Additional mapped sets can be
# listed and will be heeded by libraries, but there are limits to the number of
# mappings which the kernel will allow when you later attempt to run a
# container.
#
# remap-uids = 0:1668442479:65536
# remap-gids = 0:1668442479:65536

# Remap-User/Group is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid or /etc/subgid file.  Mappings are set up starting
# with an in-container ID of 0 and then a host-level ID taken from the lowest
# range that matches the specified name, and using the length of that range.
# Additional ranges are then assigned, using the ranges which specify the
# lowest host-level IDs first, to the lowest not-yet-mapped in-container ID,
# until all of the entries have been used for maps.
#
# remap-user = "containers"
# remap-group = "containers"

# Root-auto-userns-user is a user name which can be used to look up one or more UID/GID
# ranges in the /etc/subuid and /etc/subgid file.  These ranges will be partioned
# to containers configured to create automatically a user namespace.  Containers
# configured to automatically create a user namespace can still overlap with containers
# having an explicit mapping set.
# This setting is ignored when running as rootless.
# root-auto-userns-user = "storage"
#
# Auto-userns-min-size is the minimum size for a user namespace created automatically.
# auto-userns-min-size=1024
#
# Auto-userns-max-size is the minimum size for a user namespace created automatically.
# auto-userns-max-size=65536

[storage.options.overlay]
# ignore_chown_errors can be set to allow a non privileged user running with
# a single UID within a user namespace to run containers. The user can pull
# and use any image even those with multiple uids.  Note multiple UIDs will be
# squashed down to the default uid in the container.  These images will have no
# separation between the users in the container. Only supported for the overlay
# and vfs drivers.
#ignore_chown_errors = "false"

# Path to an helper program to use for mounting the file system instead of mounting it
# directly.
#mount_program = "/usr/bin/fuse-overlayfs"

# mountopt specifies comma separated list of extra mount options
mountopt = "nodev"

# Set to skip a PRIVATE bind mount on the storage home directory.
# skip_mount_home = "false"

# Size is used to set a maximum size of the container image.
# size = ""

[storage.options.thinpool]
# Storage Options for thinpool

# autoextend_percent determines the amount by which pool needs to be
# grown. This is specified in terms of % of pool size. So a value of 20 means
# that when threshold is hit, pool will be grown by 20% of existing
# pool size.
# autoextend_percent = "20"

# autoextend_threshold determines the pool extension threshold in terms
# of percentage of pool size. For example, if threshold is 60, that means when
# pool is 60% full, threshold has been hit.
# autoextend_threshold = "80"

# basesize specifies the size to use when creating the base device, which
# limits the size of images and containers.
# basesize = "10G"

# blocksize specifies a custom blocksize to use for the thin pool.
# blocksize="64k"

# directlvm_device specifies a custom block storage device to use for the
# thin pool. Required if you setup devicemapper.
# directlvm_device = ""

# directlvm_device_force wipes device even if device already has a filesystem.
# directlvm_device_force = "True"

# fs specifies the filesystem type to use for the base device.
# fs="xfs"

# log_level sets the log level of devicemapper.
# 0: LogLevelSuppress 0 (Default)
# 2: LogLevelFatal
# 3: LogLevelErr
# 4: LogLevelWarn
# 5: LogLevelNotice
# 6: LogLevelInfo
# 7: LogLevelDebug
# log_level = "7"

# min_free_space specifies the min free space percent in a thin pool require for
# new device creation to succeed. Valid values are from 0% - 99%.
# Value 0% disables
# min_free_space = "10%"

# mkfsarg specifies extra mkfs arguments to be used when creating the base
# device.
# mkfsarg = ""

# Size is used to set a maximum size of the container image.
# size = ""

# use_deferred_removal marks devicemapper block device for deferred removal.
# If the thinpool is in use when the driver attempts to remove it, the driver
# tells the kernel to remove it as soon as possible. Note this does not free
# up the disk space, use deferred deletion to fully remove the thinpool.
# use_deferred_removal = "True"

# use_deferred_deletion marks thinpool device for deferred deletion.
# If the device is busy when the driver attempts to delete it, the driver
# will attempt to delete device every 30 seconds until successful.
# If the program using the driver exits, the driver will continue attempting
# to cleanup the next time the driver is used. Deferred deletion permanently
# deletes the device and all data stored in device will be lost.
# use_deferred_deletion = "True"

# xfs_nospace_max_retries specifies the maximum number of retries XFS should
# attempt to complete IO when ENOSPC (no space) error is returned by
# underlying storage device.
# xfs_nospace_max_retries = "0"

[Conan-Kudo]

/kind bug

[Conan-Kudo]

Gah, nevermind, the issue is that I'm missing ARG statements to map to this.

[Conan-Kudo]

This is actually an issue, as it seems there is no way to propagate to buildah bud any environment variables...

[rhatdan]

Have you tested this against the latest buildah or against the main branch, if this works there, then you shouldbe opening a RHEL bug and not reporting it here.

[Conan-Kudo]

It's a problem on buildah 1.18 on Fedora 33 too, as well as buildah 1.19 in updates-testing.

[rhatdan]

I am no expert, but out tests are declaring the ARG then it works.

$ cat /tmp/Containerfile
FROM ubi8
ARG PHP_VERSION
RUN echo ${PHP_VERSION}

$ buildah bud --build-arg=PHP_VERSION=1.2.3 /tmp
STEP 1: FROM ubi8
STEP 2: ARG PHP_VERSION
STEP 3: RUN echo ${PHP_VERSION}
1.2.3
STEP 4: COMMIT
Getting image source signatures
Copying blob 92538e92de29 skipped: already exists
Copying blob eb7bf34352ca skipped: already exists
Copying blob 01382447cf32 done
Copying config f0359bec28 done
Writing manifest to image destination
Storing signatures
--> f0359bec28f
f0359bec28fdf7c0ddb783fa9ad2165acbf1c4d8f9e6063db66bfdf6acd58897

Without the ARG command, I see the same error as you.

Checking with Docker, it requires the ARG also.

 docker build /tmp/d2
Sending build context to Docker daemon  2.048kB
Step 1/2 : FROM alpine
 ---> f70734b6a266
Step 2/2 : RUN echo ${PHP_VERSION}
 ---> Running in 81179e2da39f

Removing intermediate container 81179e2da39f
 ---> efedc04d43e1
Successfully built efedc04d43e1
sh-5.0# docker build /tmp/d2
Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM alpine
 ---> f70734b6a266
Step 2/3 : ARG PHP_VERSION
 ---> Running in 300c0db284b3
Removing intermediate container 300c0db284b3
 ---> 4f7d43f045cd
Step 3/3 : RUN echo ${PHP_VERSION}
 ---> Running in 78d3d365a075

Removing intermediate container 78d3d365a075
 ---> feec4bd6fede
Successfully built feec4bd6fede

[rhatdan]

$ buildah version
Version:         1.19.4
Go Version:      go1.15.7
Image Spec:      1.0.1-dev
Runtime Spec:    1.0.2-dev
CNI Spec:        0.4.0
libcni Version:  
image Version:   5.10.1
Git Commit:      
Built:           Wed Dec 31 19:00:00 1969
OS/Arch:         linux/amd64

[mythi]

This issue looks very similar what I observed with #2424 earlier

[Conan-Kudo]

It probably is. It last worked in Buildah 1.11.6.

[rhatdan]

This works the same way as Docker does, if you don't specify the ARG to use, then the Environment variable is not expanded.
If you show me this working on current docker, then reopen.